Various industries use devices that hold a liquid or allow a liquid to pass therethrough. Such devices have widespread use in biotechnology, optoelectronics, and micro-electromechanical systems (MEMS). As one example, systems for biological research may use fluidic devices called flow cells to conduct designated reactions within flow channels. The reactions (or evidence of the reactions) are imaged by a camera sub-system having an objective lens that is positioned adjacent to the flow cell. To calibrate the camera sub-system, another device is positioned where the flow cell is typically located. This other device is an optical alignment tool that appears similar to the flow cell. The optical alignment tool has an enclosed chamber that is similar to the flow channels in size and shape. The enclosed chamber is filled with a liquid that includes one or more fluorescent dyes. An interior surface that defines the enclosed chamber has metal pads with shaped openings therethrough. To align the camera sub-system, the metal pads are imaged by exciting the fluorescent dye(s) in the enclosed chamber. The shaped openings of the metal pads in the images are analyzed to determine how to align the camera sub-system.
Fluidic devices, such as the flow cells and the optical alignment tool described above, may include multiple discrete structures that are secured to one another. It becomes more challenging, however, to join these structures when features of the structures become smaller or the designs of the structures become more complex. One technique used to join the structures is referred to as “laser-welding” or “laser-bonding” in which a light beam (e.g., laser beam) is directed along the interface between two adjacent structures causing the material of at least one of the structures to melt. A weld is formed after the material cools and solidifies.
A common problem that may occur with fluidic devices is that the liquid may leak through the interfaces or through ports of the fluidic devices. In addition to this, it is often desirable for bubbles to be absent (or near absent) from the cavities where the liquid is located. Bubbles may reduce the quality of images or prevent certain mechanisms, such as liquid valves and lenses, from operating properly. Although laser-welding is effective in joining the structures, it is still challenging to create devices that limit leakage and/or that have a reduced number of bubbles.